Development of Silica-Based Monoliths for the Capture of CO2

Abstract

The synthesis of mesoporous materials in macroscopic scale, as for example, the monoliths, has been of great interest in view of the wide range of applications that this material holds. Thus, this work consists of the production of silica monoliths for the purpose of they being used in the carbon dioxide (CO2) adsorption process. The adsorbents were prepared in pure form and also with addition of heteroatoms: Al, Ti and Zr. The samples were then functionalized with pentaethylenehexamine (PEHA) by the wet impregnation method. The materials were characterized by the following techniques: X-ray diffraction (XRD), textural analysis, Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and Thermogravimetry (TG/DTG). The analyses indicated that the materials synthesized with heteroatom incorporation presented a disordered pore structure and high surface area (1387 m2/g for sample Ti/M1). In addition, they showed a significant increase in adsorption of CO2 relative to their parent sample, a fact that is not much explored in the literature. The CO2 adsorption performance tests were carried out at 30 ºC and atmospheric pressure. All functionalized materials demonstrated improved CO2 adsorption capacity relative to their starting samples. Adsorption capacities up to 111.3 mg/g were found in this work, which makes the materials developed promising candidates for the capture of CO2.

Keywords

• Adsorption
• sol-gel
• silica monolith
• metals
• functionalization